field guide to the freshwater fishes of singapore
Contents

Index of fishes
General parts of a fish
Kelvin K P Lim and Peter K L Ng
  Family Poeciliidae
This group of live-bearing toothcarps (native to Central and South America, as well as southern North America) displays obvious sexual dimorphism. Males are usually much smaller and often more brightly coloured. Their anal fins are modified into a moveable, elongated tube (gonopodium) used for transferring packets of sperm to the female's cloaca for internal fertilisation, an uncommon feature in the world of fishes.
diagram of anal fins
Anal fins of male Gambusia

diagram of anal fins
Anal fins of female Gambusia
The fertilised eggs continue to develop in the body of the female until the fry hatch and are discharged into the water (live birth).

Many species are favourite aquarium fish, being hardy, colourful and easy to breed. They are widely cultured and bred into numerous artificial colour varieties to suit the tastes of different aquarists. In this respect, they are very valuable, forming the essence of the local aquarium fish industry. Others, however have been deliberately brought around the world to combat mosquitoes. At least three species have been introduced and become firmly established in Singapore.

Genus Poecilia
photo of colourful bred guppy
Specially bred guppy
Photo: Tan Bee Hong

photo of colourful bred guppy
Another specially
bred guppy
Photo: Yip Hoi Kee
Euryhaline; ovoviviparous; omnivorous; gregarious; pelagic. Typical livebearers which consists of well known species like guppies and mollies. Although considered freshwater fish, they are also equally at home in brackish and even full strength marine water (especially mollies).

photo of pair of fishes, side view
Wild strain of Guppy
Photo: Tan Bee Hong
Guppy
Poecilia reticulata
Ikan Parit, Mata Lalat, name in chinese characters


3 cm (males), 6 cm (females). Feral, abundant.
Widespread in water channels throughout Singapore except in forest streams.

The diminutive but extremely prolific guppy was originally introduced for mosquito control (probably sometime in the early 1900s), and has since colonised many of Singapore's disturbed freshwater bodies. It is a very successful little fish, being able to survive in conditions which few other fishes can tolerate, e.g., polluted canals and even sewage tanks. They are also an all time favourite with aquarists, with numerous fancy and colourful strains having been selectively bred as part of a multi-million dollar industry. Rejected fish also provide a useful and convenient source for the subsidiary feeder fish industry. The common name is derived from the Reverend J L Guppy of Trinidad, who obtained early samples of the fish in its native land.


photo of  male fish, side view
Male Lesser Sailfin Molly
Photo: Yip Hoi Kee
Lesser Sailfin Molly
Poecilia latipinna
Ikan Parit, name in chinese characters


10 cm (males), 12 cm (females). Feral, brackish waters. Canals, drains, ponds and estuarine waters.
The Lesser Sailfin Molly is native to Mexico and the southern United States.

The males of this species have sail-like dorsal fins and make attractive aquarium pets. Many colour varieties have been bred, ranging from multi-coloured to jet-black.

They tend to thrive better in brackish water. In the aquarium, mollies seem to be rather prone to fungal infection if kept for long periods in pure fresh water.

The presence in Singapore of a larger and very similar species, the Yucatan or Greater Sailfin Molly, Poecilia velifera from Southeastern Mexico is suspected. Poecilia velifera tends to grow larger, the males reaching 15 cm and the female 18 cm in length. The dorsal fin of P. velifera has more fin rays (18 to 19) compared to P. latippina (13 to 16).
photo of whole fish, side view
Sailfin Molly (male)
Photo: Tan Bee Hong

photo of whole fish, side view
Black Sailfin Molly
Photo: Tan Bee Hong

photo of whole fish, side view
Golden Molly

photo of whole fish, side view
Piebald Molly

photo of  female fish, side view
Female Common Molly

photo of  male fish, side view
Male Common Molly

Photos: Yip Hoi Kee
Common Molly
Poecilia sphenops
Ikan Parit, name in chinese characters


12 cm. Feral, common in brackish water. Rural streams, canals, drains and ponds. Not as colourful as P. velifera or P. latipinna, but more common. The males of this species do not possess large, sail-like dorsal fins. It is mainly used to feed predatory pet fish.

Genus Gambusia
photo of  female fish, side view
Female Mosquito Fish

photo of male fish, side view
Male Mosquito Fish
Photos: Yip Hoi Kee
Mosquito Fish
Gambusia holbrookii
Ikan Parit, name in chinese characters


Euryhaline; 3 cm (males), 6 cm (females); ovoviviparous; omnivorous; gregarious. Feral, common. Rural streams, canals, drains and ponds.

Native to southern United States and Mexico, this unassuming little fish has been brought round the
world (previously known as Gambusia affinis) to combat mosquito larvae, hence its name. It is highly adaptable and prolific. Although seldom kept as an ornamental fish due to its drab colours, it is collected for the feeder fish industry.
Introduction
Freshwater habitats
Fishes in Singapore
Conservation
Amazing Fishy Facts
About the guidebook
 
From A Guide to Common Freshwater Fishes of Singapore by Kelvin K P Lim and Peter K L Ng
Published by the Singapore Science Centre and sponsored by BP

@Raffles Museum of Biodiversity Research and Singapore Science Centre